(a) Field of the Invention:
The present invention relates to a microscope and, more specifically, to an electric system for driving a revolver and a stage.
(b) Description of the Prior Art:
A conventional electric microscope, for example, as shown in FIG. 1, is provided with an electric revolver 1, a plurality of objectives 2 attached to the electric revolver 1, a stage 3 for placing a sample P, an electric focusing device 4 moving the stage 3 to a vertical direction, that is, an optical axis direction and focusing by moving the sample P to the focal plane of the objective 2, a switch 5 indicating moving direction of the stage 3, and the like. Also, the electric focusing device, for example, is concretely formed by a stage moving mechanism as shown in FIG. 2 comprising a movable portion 6 fixing the stage 3 to the upper face, a movable portion guide 7 fixed to the body of the microscope and guiding the movable portion 6 to a vertical direction, that is an optical axis direction, a rotary shaft 8 pivotally mounted to the movable portion guide 7 and connected with the movable portion 6 through a rack and pinion mechanism, manually operated knobs 9 fixed to the ends of the rotary shaft 8, a gear 10 fixed to the rotary shaft 8, a motor 11 fixed to the body of the microscope, and a driving gear 12 fixed to the driving shaft of the motor 11 and engaged with the gear 10 and a stage moving control circuit as shown in FIG. 3 comprising a switch circuit 13 having the switch 5, a rotary direction controlling circuit 14 for determining the rotary direction of the motor 11 by the signal from said switch circuit 13, and a motor driving circuit 15 for rotating the motor 11 to the rotary direction indicated by the signal from the rotary direction controlling circuit 14.
By the way, as the conventional electric focusing device described above moves vertically the stage 3 at a constant speed, when observation is carried out by an objective with a low magnification, that is, an objective with a large focal depth, a moving speed is too low and it takes time to bring the sample to the focal plane. On the contrary, when observation is carried out by an objective with a high magnification, that is, an objective with a small focal depth, as a moving speed is too high and it is difficult to obtain an image, the operation can not be easily performed and consequently there is a problem that it takes time to perform a focusing work. Also, as the motor 11 and the rotary shaft 8 are always in a connected state, even when the focusing work is manually performed by using the manually operated knobs 9, the knobs 9 are tight to be very difficult of use. Furthermore, as the conventional device is formed so that the electric revolver 1 and the electric focusing device 4 are independently operated, there is danger that the sample may be damaged when the objective is changed from a low magnification to a high magnification. That is, when focusing is to be performed by the objective with a low magnification, the stage sometimes is positioned farther upward than the focal plane of the objective due to its large focal depth. In this state, if the electric revolver 1 is rotated to change to the objective with a high magnification, as an operating distance of said objective is short, the top of the objective may contact the sample P to damage it. Especially, in the case of a sample without a glass cover or a sample only putting a glass cover, the damage of the sample is fatal. In other words, the conventional electric microscope, as mentioned above, has provided nothing but the structure that the stage and the revolver are merely driven by the motor and has never taken such consideration that both the stage and the revolver are systematically controlled by being interlocked with each other or that a manual operatin can be also facilitated.